Method for promoting formation of fruit abscising layer

ABSTRACT

Fruit abscising compositions for facilitating the harvest of fruits, especially citrus fruits, which comprises as an active ingredient at least one thiamine derivative selected from the group consisting of THIAMINE ESTERS AND THEIR SALTS WITH INORGANIC ACIDS; AND S-acyl and disulfide derivatives of thiol-type thiamines, their esters and their salts with inorganic acids AND AN AGRICULTURALLY-ACCEPTABLE CARRIER.

United States Patent [191 Takahashi et al.

[ 1 METHOD FOR PROMOTING FORMATION OF FRUIT ABSCISING LAYER [75] Inventors: Shogo Takahashi, Tokyo; Takayasu Yamada, F ujisawa; Hiromi Okudaira, Soka, all of Japan [73] Assignee: Sankyo Company Limited, Tokyo,

Japan [22] Filed: Dec. 17, 1971 [21] Appl. No.: 209,403

[30] Foreign Application Priority Data Dec. 27, 1970 Japan 45/127181 [52] US. Cl 71/90, 71/86, 71/88 [51] Int. CL. A01" 9/12 [58] Field 01 Search 71/90, 74, 92; 424/255 [56] References Cited UNITED STATES PATENTS 1 Miller 71/74 Jan. 8, 1974 3,321,293 5/1967 Sousa 71/74 2,392,518 1/1946 Barnhill 71/90 3,472,735 10/1969 Nishikawa e=t a1. 424/255 3,432,504 3/1969 Goetze-Claren 424/255 2,205,807 Bjorksten 71/90 Primary ExaminerGlennon H. Hollrah Att0rneyT0ren and McGeady [57] ABSTRACT and an agriculturally-acceptable carrier.

1 Claim, No Drawings METHOD FOR PROMOTING FORMATION OF FRUIT ABSCISING LAYER This invention relates to a new use of certain thiamine derivatives as a fruit abscising agent.

More particularly, this invention relates to a fruit abscising composition for facilitating the harvest of fruits which comprises as an active ingredient at least one compound selected from the group consisting of thiamine esters and their salts with inorganic acids;

and

S-acyl and disulfide derivatives of thiol-type thiamines,

their esters and their salts with inorganic acids and an agriculturally-acceptable carrier.

The term thiamine ester as used herein means to refer to the corresponding O-acyl thiamine derivative.

Also, it is connected with a method for facilitating the harvest of fruits by accelerated abscission layer formation which comprises applying to fruited trees an effective amount to accelerate fruit abscission of at least one compound selected from the thiamine derivatives as specified hereinabove.

Heretofore, in many countries various fruits, for example, orange, lemon, olive, plum, chestnut, grape and the like have been principally harvested by hand with a great number of farm labours and it has been a longpending problem in the art to effectively save the labour for gathering of ripe fruits. Some previous attempts have been made to attain such purpose. For instance, mechanical vibration was applied to fruited trees in branches, main braches and/r twigs thereof by means of a specific vibrator, thereby to cause the fruits to fall off. However, this prior method was not satisfactory since the harvested fruits and the vibrated branches and leaves of the tree were sometimes seriously damaged through forced mechanical power.

On the other hand, although another attempt was made wherein a chemical agent was applied to fruited trees a, completely favourable result was not obtained because of simultaneous occurrence of the fall of leaves and the appearance of an adverse effect on the harvested fruits during storage.

As a result of our extensive studies to develop a new and effective fruit abscising agent, it has been unexpectedly found that the above-defined thiamine derivatives exert a superior biological effect to accelerate the formation of anabscission layer between the stem and the fruit adherent thereto in a fruit tree, which leads to the facilitation of the falling of the fruit to be harvested, without the prior art disadvantages, and the present invention is based upon the discovery set forth just hereinabove.

It is, accordingly, an object of this invention to provide a new and unique fruit abscising composition which comprises as an active ingredient at least one of the specific thiamine derivatives and an agriculturallyacceptable carrier.

it is another object of this invention to provide a new and valuable method for the facilitation of the harvest of fruit which comprises applying to fruited trees an effective amount of the above-defmed thiamine derivatives.

These and other objects of this invention will become apparent from the following detailed description.

The active ingredients which may be employed in this invention, i.e., the thiamine derivatives as specified above are all known in the art and they may be readily prepared according to any of conventional techniques known per se.

Representative examples of the active ingredient in this invention are listed below, but they are not intended to be limiting the scope of this invention.

The ester components of the active thiamine derivatives in this invention may be any of those capable of constituting an ester portion of various known thiamine ester derivatives, but the phosphates are preferred in view of their activities. Among the above-listed thiamine derivatives, advantageously employed is the derivative number 4, Le, S-benzoyl-thiamine-O- monophosphate.

The inorganic acid which may constitute a salt with the active thiamine derivative may also be any of those acids commonly utilized in the art for the formation of various therapeutically active thiamine salts, but illustrative of the inorganic acid are hydrochloric, sulfuric and nitric acids.

In preparing the present fruit abscising composition, the active thiamine derivatives as set forth above may be conveniently formulated according to a known means into various forms, including liquids, dusts, wettable powders and the like.

Liquids may be prepared by dissolving or suspending the active compound in an agriculturally-acceptable liquid carrier, i.e., a suitable solvent with or without one or more of known adjuvants commonly employed in the art, such as, emulsifying agents, wetting agents, or dispersing agents. Suitable solvents include water,

alcohols, such as, methanol or ethanol, acetone, benzene, toluene, xylenes, solvent naphtha, petroleum ether, the mixture thereof and the like. Suitable adjuvants may be any of those which is ordinarily employed in the art, and include, for example, the condensation products of alkyleneoxides with phenols or organic acids, alkylarylsulfonates, dialkyl sulfosuccinate, polyoxyethylene ether or ester derivatives of alcohols or acids and the like.

Dusts may be prepared by admixing said active compound with an inert agriculturally-acceptable solid carrier by a conventional procedure. Suitable solid carriers for use in this invention include, for example, talc, pyrophylit'e, kieselguhr, clay, bentonite, diatomaceous earth, kaolin, precipitated chalk and the like.

Wettable powders may be prepared by mixing said active compound with one or more of the aforementioned solid carriers and suitable dispersing agents. Suitable dispersing agents include, for example, those aforementioned adjuvants, such as, alkylbenzenesulfonates, lignosulfonates or polyoxyalkylene glycol ethers or esters.

Other preparations may be suitably formed by those skilled in the art according to the prior art teachings.

as mandarin orange tree (Citrus Unshiu), orange tree (Citrus Natsudaidai), Hassaku tree (Citrus Hassaku), navel orange tree and Valencia orange tree (Citrus sinensis), lemon tree (Citrus Limon); and stone fruit The concentration of the active compound in the fin- 5 trees, such as, olive tree (Olea europeaea), cherry tree ished composition of this invention may be usually (Prunus avium), cherry plum tree (Prunus cerasifera), within the range of about 0.1 to about 98 percent by apricot tree (Prunus Armeniaca), plum tree (Prunus weight, and preferably of about 1.0 to about 70 percent Mume), palm tree (Phoenix dactylifera), grape tree by weight, based upon the total weight of the finished i is f Walnut tree g i a); n composition. The concentration of the active comthe llkepound in the present composition ready for use may be 7 It is also to be noted that many of the active thiamine usually of a lower range than that of the finished comderivatives in the present composition are known as position as mentioned just above and will largely detherapeutic and nourishing agents in medicinal field pend upon such factors as the kind of fruit tree, the and thus the active thiamine derivatives in this invenform of a composition of the specific active ingredient, tion can be surely expected to show neither phytotoxicthe ripening degree of fruit and the like, usually about ity against the fruit trees applied nor harmful effects 0.001 to about 10 percent being employed. upon human beings and domestic animals, accompa- It should be, however, understood that the amount of nied with favourable storage of the treated and haran active compound in the composition of this invenvested fruits. tion is not critical feature of this invention. Two or In order to demonstrate the superior fruit abscission more of said active ingredients may be advantageously effect of this invention and some specific embodiments incorporated into the composition of this invention. of this invention, examples are given hereinbelow.

lt should be avoided that'other known agricultural chemicals, for example, insecticide, fungicide, acari- EXAMPLE 1 cide and the like be incorporated into the present in- Three groups of mandarin orange trees (Citrus vention, if it would be expected that residual toxicity Unshiu) which were 60 years old and were bearing a might appear in the harvested fruits. great number of fruits were treated by uniformly spray- The method for facilitating the harvest of fruit of this ing thereto a sufficient amount of one of the active invention comprises applying fruited trees by uniformly compounds indicated below in the form of an aqueous spraying them on both sides of the leaves, branches, solution or emulsion having the concentration of 1,000 fruits and the like with an effective amount of the acpm. tive compound to exert the desired effect of forming an After 12 days of the treatment, constant vibration abscission layer, usually before about 1 to 3 weeks of was applied to the tree in its branches by means of a a possible harvest time. Then, a suitable-preferably conventional vibrator. constant-vibration is usually applied to the trees, for ex- The numbers of falling fruits and of falling leaves in p in the branches, main branches and/0r Stems each group were measured, respectively, and the averlhereof y means of a mechanical Vibrator commonly age falling rate of fruits and the average number of fallemployed in the art, thereby to cause the fruits fallen ing leave were calculated. off. The results are given in the following Table l.

The method of this invention may be conveniently The damages in the fruit surface was no greater than applied to any of fruit trees, especially citrus trees such th obtained with the prior hand-working.

TABLE 1.MANDARIN ORANGE TREES,

Falling rate of fruits (percent) Rate of fruits Rate of having fruits incomhaving plete ab- Holding Damage Degree abscission scission rate of on the Number of test layers layers fruits 3 fruit 4 falling compound (percent) (percent) Total (percent) surface leaves 5 75.9 18.6 94.5 5.5 :1: 84.5 3.4 87.9 12.0 :1: :1: 98.3 1.2 99.5 0.5 85.7 3.2 88:9 10.2 57.8 22.9 80.7 19.3 55.7 25.6 92.3 7.7 54.8 25.2 89.5 10.5 78.5 9.7 88.2 11.8 :1: 80.8 10.8 91.6 8.4 a: 94.5 3,1 97.5 2.3 12 80.0 9.7 89.7 10.3 H2O (control) 34.0 25.4 59.4 40.5

*A mixture of No. 1, No. 2, and No. 3.

1 The number of the test compound is the same as illustrated hereinabove.

Fruit having abscission layers means the one that fell off from the tree by smooth separation from the fruit stem thereof without any damage. "Fruit having incomplete abscission layers means to include those fruits having the damaged stems, the ones that fell off with the broken peels and the ones that fell ofi because of breakdown of the stems.

8 "Holding rate of fruits means a rate of fruits that do not fall ofi by a mechanical vibratron but are harvested by hand at a harvesting stage.

4 Damage on the fruit surface means a degree of phytotoxicity developing on the fruit surface by the test compound:

N o phytotoxicity was observed. :l=: Only a few damaged oil foams on the fruit surface were observed. +2 Damaged oil foams on the fruit surface were observed. 5 Degree of falling leaves" means a number of the leaves that fell off by a mechanical vibration;

: The same degree as observed in the control. ':i:Z Somewhat higher degree than that observed in the control.

EXAMPLE 2 Four groups of plum trees (Prunus Mume: variety, Kobungo) l5 years of age and which were bearing a great number of fruits were treated with the active compound indicated below in the form of an aqueous solution or emulsion having the concentration of 1,000 ppm by uniformly spraying over the whole crown of the tree to a sufficient extent.

After days of the treatment, constant vibration was applied to the tree in its main branches by means of a conventional vibrator.

The numbers of falling fruits and of falling leaves as well as remaining leaves were investigated, respec' tively.

The results are given in the following Table 2.

The attachment of the fallen fruit to the fruit stem as well as the damage upon falling were also observed.

* a mixture of No. I, No. 2 and No. 3

The number of the test compound is the same as illustrated hereinabove.

Degree offalling leaves is evaluated according to the following ratings; only a few fallen leaves were observed.

i: about 100 fallen leaves were observed.

+2 about 300 fallen leaves were observed.

H: about 500 fallen leaves were observed.

pound selected from the group consisting of:

thiamine monophosphate,

thiamine diphosphate,

thiamine triphosphate, S-benzoyl-thiamine-O-monophosphate, S-(2-hydroxybenzoyl)-thiamine-O-monophosphate, S-benzoyl-thiamine-O-acetoxyacetate, S-benzoyl-thiamine-O-y-ethoxybutyrate, S-(2-furoyl)-thiamine-O-acetoxyacetate, thiamine propyl disulfide,

thiamine tetrahydrofurfuryl disulfide, thiamine-O-monophosphate disrulfide, and

carbothiamine. 

